Research The first international clinical guideline for Kleefstra syndrome Katerina Tzimourta, February 12, 2026August 20, 2026 An international team of 43 experts and patient representatives from 15 countries has published the first comprehensive, evidence-based clinical guideline for EHMT1-related Kleefstra syndrome. The 66 recommendations organize diagnosis, routine monitoring, multidisciplinary care, and lifelong support.